Toothbrush

ABSTRACT

The invention relates to a toothbrush handle part having a handle part neck that can be inserted into the connecting piece of an attachment. Said attachment comprises a coupling device having at least one engaging piece for locking with the connecting piece of the attachment. The invention also relates to the above attachment comprising an attachment head and a tubular connecting piece connected to the attachment head, the connecting piece being placeable on the handle part neck of the toothbrush handle part and having a coupling device for locking the connecting piece on the handle part neck. The invention is characterized in that the axial movement in the longitudinal direction of the handle piece effects actuation of the coupling device and the transverse movement effects the locking. The toothbrush handle part is characterized in that its coupling device has a coupling piece which is axially movable in the longitudinal direction of the handle part, said coupling piece being received in such a manner that an axial movement of the coupling piece produces a transverse movement of the engaging piece of the coupling device at a right angle to the longitudinal direction of the handle part. The axial actuation movement can be produced when the attachment is placed onto or removed from the handle part neck.

The present invention relates to a preferably electric toothbrush. The invention thus relates to the toothbrush handle part having a handle part neck that can be inserted into the connecting piece of an attachment, for instance a brush attachment, said handle part neck is provided with a coupling device having at least one engaging part for form-fitting and/or frictionally engaged interlocking thereof with the connecting piece of the attachment. The invention also relates to said attachment, which may form a brush attachment, for example, having an operating head and connected to the operating head a tubular connecting piece that can be placed onto the handle part neck of the toothbrush handle part, wherein the connecting piece has a coupling part for form-fitting and/or frictionally engaged locking of the connecting piece on the handle part neck.

-   An electric toothbrush is known from EP 0 500 537 B1, in which the     brush attachment is connected both to a shaft-like handle part neck     of the toothbrush handle part projecting from the front side and to     a drive shaft projecting therefrom. The handle part neck is formed     approximately in the shape of a cylindrical frustum, so that the     approximately tubular connecting piece of the brush attachment can     be attached with a precisely clamping fit onto the handle part neck.

For attachable brush attachments of this type, an unintentional loosening of the attachment fastening should be prevented while the toothbrush is being operated and an easy attaching and detaching process should be possible. In order to achieve this, the fit between the handle part neck and attachment brush was selected so tight until now that the brush attachment could be attached on or removed from the handle part neck only with great expenditure of effort. To the extent that detent locking connecting means were provided between the brush attachment and toothbrush handle part, however, the tolerances that are required for a simple snap-in engagement often interfere with a zero-backlash and precise fit of the connection.

-   From this, the object of the present invention is to create an     improved toothbrush, an improved toothbrush handle part and/or an     improved attachment for such a toothbrush handle part in which     disadvantages of the prior art are avoided and advantageously     improving upon the latter. Preferably a connection between the     attachment and toothbrush handle part that that can be operated     easily and with little expenditure of effort should be created, that     firmly supports the attachment on the toothbrush handle part and     largely prevents loosening of the brush attachment.

The named object is achieved by a toothbrush handle part according to claim 1, an attachment preferably for such a toothbrush handle part according to claim 28, as well as a toothbrush according to claim 43. Preferred embodiments are the subject matter of the dependent claims.

It is thus proposed that the handle part of a toothbrush has on its handle part neck a coupling device having at least one engaging part provided for a form-fitting and/or frictionally engaged interlocking with a connecting piece of an attachment, for example a brush attachment, wherein the coupling piece is movable in the longitudinal direction of the handle part. The coupling piece is preferably pushed away axially from the grip portion of the toothbrush handle part by a spring element, so that when the attachment is not attached, the coupling piece is located in a defined position relative to the handle part, in which the attachment can be attached unimpeded. The handle part neck is preferably formed as one piece with the housing of the handle part.

The coupling device on the handle part neck advantageously operates with an axial movement in the longitudinal direction of the handle part and with a transverse movement transversely to the longitudinal direction of the handle part, wherein advantageously the axial movement in the longitudinal direction of the handle part effects the actuation of the coupling device and the transverse movement effects the locking. The toothbrush handle part is characterized in that the coupling device thereof has a coupling piece that is axially movable in the longitudinal direction of the handle part and is supported and/or formed in such a way that an axial movement of the coupling piece produces a transverse movement of the engaging part of the coupling device transversely to the longitudinal direction of the handle part.

The axial actuation movement can advantageously be produced by the attachment while being attached to or removed from the handle part neck. The attaching or removing of the attachment can be used, so to speak, to produce a locking or unlocking movement transversely acting on the coupling device of the handle part. According to a further aspect, the attachment is characterized in that its coupling part has on an internal cylindrical surface an outwardly oriented depression into which the engaging part of the coupling piece of the handle part can be moved, and an abutting surface for the axial pushing back of the coupling piece of the handle part when the connecting piece is placed onto the handle part neck. Said abutting surface on the coupling part of the attachment is advantageously adjusted in terms of the shape and position thereof to the coupling piece of the handle part, such that the abutting surface captures the coupling piece of the toothbrush handle part when the attachment and toothbrush handle part are being attached to one another and axially pushes same back toward the grip portion of the toothbrush handle part, so that the locking is effected quasi automatically during the process of placing on the attachment.

In order to produce the transverse movement of the engaging part of the coupling device of the handle part that effect the locking, an expanding mechanism is advantageously provided between the handle part neck and the coupling piece of the toothbrush handle part, whereby the aforementioned engaging part of the coupling device of the handle part is expanded outward transversely to the longitudinal direction of the handle part when said coupling piece is moved in the axial direction toward the handle part. Advantageously, it is the coupling piece itself that is expanded outward by said expanding mechanism when a corresponding axial movement takes place, so that said engaging part can be arranged directly on the coupling piece, preferably integrally formed as one piece.

Said expanding mechanism can be designed in various ways. For example, the expanding could be effected by a pair of oblique surfaces. For example, the coupling piece could move up onto an oblique surface provided on the handle part neck, such that the coupling piece is pressed outward when it is being pushed back toward the grip portion.

Preferably, however, the expanding mechanism is designed in the form of a positive guide that prevents a transverse movement of the coupling piece without an axial movement of the coupling piece and/or vice versa. The expanding mechanism is accordingly designed in such a way that it not only ensures that the coupling piece is pushed outward during a corresponding axial movement, but also that it is pulled inward during the opposite axial movement.

In particular, the coupling piece of the coupling device of the handle part can be supported by means of a link guide on the handle part neck comprising at least one link that, in an advantageous embodiment, is hinged rotatable with one end thereof to the handle part neck and hinged rotatable with the other end thereof to the coupling piece, wherein the pivot axes are advantageously oriented transversely to the longitudinal direction of the handle part.

In principle, it may be sufficient to hinge the coupling piece using only one link in the area of the engaging part in order to achieve the desired expanding in the area of the engaging part. The coupling piece in this case could be guided on the handle part neck in the longitudinal direction on a section arranged at a distance from the engaging part, so that an overall double-link type design would result. Preferably, however, the coupling piece is hinged to the handle part neck by means of a parallelogram link guide having at least two links that are arranged approximately parallel to one another, so that the coupling piece can be displaced parallel on a path of movement defined by the links, essentially without a rotational component. The parallelogram link guide is designed in such a way that during an axial movement of the coupling piece in the longitudinal direction of the handle part a transverse movement component is produced transversely thereto. Advantageously, the links of the parallelogram link guide are arranged in such a way that initially, i.e. in the area of the non-locking position of the coupling piece, a stronger transverse movement component is produced during an axial movement than at the other end of the axial actuation path, i.e. in the area of the locking position.

Advantageously the coupling piece can be guided on a path of movement that is designed to radially over-press the coupling piece at one end of the path of movement, prior to reaching the locking position of the coupling piece, in which the coupling piece is moved further out transversely to the longitudinal direction of the handle part than in the locking position itself. Thus, during the outward pivot movement of the coupling piece, it moves past a dead center position before the coupling piece assumes its final locking end position. In this manner a self-retaining fixing can be achieved in the locking position that can be overcome only by means of a defined force onto the attachment in the axial direction.

In particular, the links of the parallelogram link guide may be arranged in such a way that, when pivoting into the locking position of the coupling piece, the links moves past a position that is oriented perpendicular to the longitudinal direction of the handle part, whereas the links take an acutely inclined position relative to the longitudinal direction of the handle part in both end positions of the coupling piece of the handle part. Advantageously, the links can be arranged in such a way that they are inclined differently acutely in said end positions of the coupling piece. While the links can be inclined at an angle relative to the longitudinal direction of the handle part between approximately 20° and 60°, preferably 30° to 50° in the moved-in unlocked position of the coupling piece, they are advantageously inclined at an angle of approximately 70° to 89°, preferably 75° to 85° relative to the longitudinal direction of the handle part in the locking position of the coupling piece. These angles should be understood as values, since the perpendicular 90° position relative to the longitudinal direction of the handle part is advantageously moved between both end positions, such that the links are inclined to different sides with respect to said 90° position relative to the longitudinal direction of the handle part in the aforementioned angle and end positions.

Alternative to such a pivot link guide, the coupling piece can also be expanded by means of a sliding guide, wherein the coupling piece is advantageously positively guided in such a way that an axial movement of the coupling piece is positively converted into a radial movement. Advantageously the positive guidance exists in both directions, i.e. when the coupling piece is moved in one direction, the coupling piece is pushed outward, and when it is moved in the opposite direction, it is pushed inward.

Said sliding guide is advantageously designed as a connecting link guide that preferably has a guiding slide provided in the coupling piece as well as at least one guiding projection engaging therein provided on the handle part neck. The coupling piece forms a slide block, so to speak, that is expandable via the connecting link guide along a specified path. The degree and height of the expanding movement can be controlled by the incline of the connecting link guide. Advantageously the connecting link guide comprises a plurality of guide segments having different inclines, such that, depending on the axial position of the coupling piece, different expanding movements take place. In particular, the connecting link guide can comprise starting and end sections that have only a low incline, or advantageously a substantially incline-free course parallel to the longitudinal direction of the handle part between which a guide means section of greater incline is provided. In this manner it can be achieved that, in the end sections, the coupling piece can be held in its respective position substantially free from axial forces by means of the only slightly or not at all inclined guide sections. By means of the more acutely inclined guide means section, on the other hand, the desired expanding movement can be attained. Once this is completed, the connecting link guide moves onto a plateau, so to speak, by means of which the respective position is maintained. Said starting and end sections can optionally be slightly inclined in opposite directions toward said middle section, so that during the moving into the end position a slight over-pressing of the coupling piece, so to speak, takes place and the latter reliably remains in its respective end position.

The coupling device can have a preferably mechanically operating control device assigned thereto that controls the toothbrush drive according to the position of the coupling device. In particular, the control device can have retarding means that block, switch off, or retard or slows the toothbrush drive when the engaging section of the coupling device is not in the locking position thereof. In this manner, the toothbrush drive can be prevented from moving when the brush attachment is not properly attached on the handle part. Said retarding means can be designed in various ways, wherein it could, in principle, be conceivable to design the retarding means using control- or software-technology based solutions. However, a mechanical design of the retarding means is preferred, wherein the retarding means can advantageously comprise an engaging surface on the coupling piece that can move into engagement with a drive shaft of the handle part, in particular it can be pushed onto the drive shaft in the moved-in non-locking position of the coupling piece. In particular the retarding means can comprise flattened regions on the drive shaft and on said coupling piece of the handle part that can be moved onto one another. When the coupling piece presses with its flattened region onto a corresponding flattened region on the drive shaft, the latter can no longer rotate. Said flattened regions are advantageously arranged on the circumferential surface. The retardation of the toothbrush drive in the non-locking position of the coupling piece is assisted by the spring element, since the spring element pushes the coupling piece away from the grip portion of the toothbrush handle part in the axial direction, i.e. into the unlocking position, when the attachment is not attached.

Advantageously, said retarding means can cooperate with an electronic cut-off for the drive motor. In particular, said control device can have a preferably electronic cut-off device that shuts off the drive motor when the drive shaft is retarded. Once the electronic shut-off device detects that the drive shaft of the toothbrush cannot rotate freely, the drive motor is shut off in order to preserve the motor and in particular also the battery. Detecting the retarded condition of the drive shaft can, in principle, take place in various ways. For example, a position sensor could be provided that detects the position of the aforementioned coupling piece. If the coupling piece is located in its retarding position the drive motor is then shut off. Advantageously, however, shutting off the motor can also take place by means of its power intake. In particular, the aforementioned cut-off-device can comprise detection means for detecting the motor current and switch off the drive motor when the motor current exceeds a specified motor current level. This occurs when the drive shaft is blocked or retarded.

Such a mechanical retardation of the drive shaft of the toothbrush handle part when the attachment is not attached, in combination with an electronic cut-off of the drive motor makes it possible to achieve a very simple travel safety mechanism including battery protection. All that is required in order to prevent the toothbrush handle part from being switched on accidentally is to pull of the attachment from the toothbrush handle part. Even if this is placed loosely, for example, into a suitcase the storage battery of the toothbrush cannot discharge accidentally.

In order to be able to utilize the axial attaching movement of the attachment onto the handle part neck for actuating the coupling device, the coupling piece of the handle part has a capture section provided thereon that captures an abutting surface provided on the connecting piece of the attachment when the attachment is being placed onto the handle part neck, so that the abutting surface moves the capture section and thereby the coupling piece in the axial direction toward the grip portion of the toothbrush handle part when the attachment is being attached onto the handle part neck. In particular an abutting surface pair extending transversely to the longitudinal direction of the handle part and longitudinal direction of the attachment can be provided on the coupling piece of the handle part and on the coupling part of the attachment, said abutting surface pair being matched to one another in terms of the position and orientation thereof in such a way that the abutting surfaces are positively moved into engagement with one another when the attachment is being placed onto the handle part neck, thereby effecting the desired axial displacement of the coupling piece of the handle part. Advantageously, the mutually capturing abutting surfaces are designed in such a way that not only the axial actuating movement of the coupling piece of the handle part is effected, but the transverse movement of the coupling piece of the handle part that is designed to occur in the process is made possible as well. In particular, the coupling piece of the handle part, or its abutting surface, can slide off transversely to the longitudinal direction of the handle part on the abutting surface of the attachment. The mutually capturing sections on the handle part and on the attachment that effect the axial actuating movement of the coupling piece form a sliding-surface pair, so to speak, that slide off on one another when the attachment is being attached in the axial direction.

The abutting surface of the attachment is arranged directly adjoining the edge of the depression into which the coupling piece of the handle part can move. In particular, said abutting surface can transition flush into the edge surface of the depression and/or at the same time form at least part of the latter edge surface of the depression. Advantageously, said abutting surface will be situated at the edge section of the depression that, viewed in the longitudinal direction of the attachment, is located deepest in the tubular attachment piece of the attachment.

In order to, conversely, effect an automatic releasing of the coupling piece and axially move same along when the attachment is being removed from the toothbrush handle part, the attachment and the coupling piece of the handle part have provided thereon a driving-surface pair that advantageously extends transversely to the axial direction and forms, in the aforementioned manner, a sliding-surface pair so in order to permit a sliding off transversely to the longitudinal direction of the handle part and attachment, thereby permitting the unlocking movement of the coupling piece transversely to the longitudinal direction of the handle part. Advantageously the two driving-surface pairs are measured and adjusted to one another in the transverse direction, i.e. transversely to the longitudinal direction of the handle part and attachment, respectively, such that they overlap one another and are in engagement against one another in the expanded locking position of the coupling piece, but are offset in the transverse direction from one another in the moved-in unlocked position of the coupling piece. In other words, said driving surfaces, when the attachment is being removed, move out of engagement no later than at the end of the axial movement of the coupling piece of the handle part in order to permit the attachment to be removed completely.

In a particularly advantageous embodiment, said driving surfaces can be formed by an edge surface of the depression provided on the attachment on one hand, and by an edge surface of the detent locking projection on the coupling piece of the handle part on the other hand, so as to drive the coupling piece when the attachment brush is being removed.

In order to ensure a precisely fitting placement and coupling of the attachment on the toothbrush handle neck even when the fitting surfaces have dirt on them, a provision is made that dirt catching recesses are provided on the handle part neck of the toothbrush handle part and/or on the connecting piece of the attachment, into which dust particles, crumbs, or the like can disappear, so to speak, when the two toothbrush parts are attached to one another, so that they do not interfere with the coupling process. Said dirt catching recesses can be provided in particular on the cylindrical or conical fitting surfaces of the handle part neck and attachment, in particular on the external cylindrical surface of the handle part neck and on the internal cylindrical surface of the connecting piece of the attachment. Alternatively or additionally, such dirt catching recesses can also be provided on the coupling piece of the toothbrush handle part and/or on the coupling piece of the attachment and/or on the engaging parts provided thereon, so that the coupling process is not impeded. For example, a provision can be made that the outer surface of the expandable coupling piece and/or the inner surface of the attachment with which it can be moved into engagement is provided with such dirt catching recesses, so that expanding the coupling piece is not impeded.

Said dirt catching recesses can be designed in various ways. In an advantageous embodiment, said dirt catching recesses can be designed in the form of a surface corrugation, in particular in the form of a longitudinal corrugation with substantially groove-shaped catching recesses extending in the longitudinal direction of the toothbrush.

These and additional features that can constitute the subject matter of the invention irrespective of their consideration in the claims either by themselves or in any sub-combination or combination thereof, will become apparent not only from the claims but also from the following description and associated drawings, in which:

FIG. 1 shows a partial sectional top view of an electric toothbrush according to a preferred embodiment showing the attachment brush thereof and, partially, the handle part thereof,

FIG. 2 shows a longitudinal section of the toothbrush from FIG. 1 along the line C-C depicting the multi-part handle part neck with the coupling piece provided thereon in the locked position thereof,

FIG. 3 shows a longitudinal section of the toothbrush from FIG. 1 along the line B-B showing the parallelogram link guide of the coupling piece of the handle part,

FIG. 4 shows a partial, schematic sectional view of the toothbrush from the preceding figures showing the connecting piece of the brush attachment being attached onto the handle part neck, with the coupling piece of the handle part not yet in its moved-out non-locking position,

FIG. 5 shows a partial, schematic sectional view of the toothbrush from the preceding figures similar to FIG. 4 showing the brush attachment being attached, in a position shortly before the coupling piece reaches an abutting surface in the connecting piece of the brush attachment and is actuated,

FIG. 6, FIG. 7 and FIG. 8 show additional positions of the coupling piece of the handle part during the continued process of attaching the brush attachment onto the toothbrush handle part in a partial, schematic longitudinal sectional view similar to FIGS. 4 and 5,

FIG. 9 shows the locked end position of the coupling piece of the handle part in the fully attached position of the attachment brush in a partial, schematic longitudinal sectional view similar to the preceding FIGS. 4 through 8,

FIG. 10 shows a partial longitudinal section of a toothbrush similar to FIG. 4 according to an additional advantageous embodiment according to which the coupling piece can be expanded via a connecting link guide, with said coupling piece shown in its moved-out, locking position, and

FIG. 11 shows a partial longitudinal section of the toothbrush from FIG. 10, with the coupling piece shown in its moved-in, non-locking position.

The toothbrush 1 shown in the figures comprises a handle part 2 and an attachment connected thereto in the form of a brush attachment 3. The handle part 2, which is shown only partially, comprises in a known manner a housing, in which a drive motor and a power supply means, for example in the form of a rechargeable battery, are situated, and on which an actuation switch is provided for switching the drive on and off. On the frontal end of the handle part 2 shown in FIGS. 1 to 3, the housing of the handle part 2 forms a handle part neck 4, that—viewed as a whole—is designed in the form of a frontally projecting frustum-shaped essentially cylindrical connecting piece that can optionally taper slightly toward its free end. Emerging from said handle part neck 4 on the front is a drive shaft 5 that can be driven, for example, in a rotatory oscillating manner.

The attachment brush 3 comprises an operating head 6 having a bristle field that is not shown in detail, which can be driven, for example, around a bristle field axis oriented approximately in the longitudinal direction of the bristles, in a rotatory oscillating manner Said operating head 6 is held by an overall tubular connecting piece 7 that can be attached onto the handle part neck 4 of the toothbrush handle part 2. In the interior of said tubular connecting piece 7 the brush attachment 3 comprises a attachable shaft 8 that can be coupled with the drive shaft 5 of the handle part so as to be integral in rotation therewith.

To fasten the brush attachment 3 on the handle part 2 a coupling insert 9 is provided in or on the tubular connecting piece 7 in the form of a separate coupling sleeve or coupling ring that is arranged in or on the tubular connecting piece 7 in an axially and/or radially fixed manner Said coupling sleeve 9 is designed overall—roughly speaking—cylindrical or slightly conical, so that the coupling sleeve 9 can be attached onto the handle part neck 4 in the axial direction, thereby permitting a largely backlash-free fastening of the brush attachment on the handle part 2. In another embodiment of a brush attachment, the connecting piece 7 is constructed physically combined with the coupling insert 9, i.e. as one piece.

As shown in FIGS. 2 and 3, the handle part neck 4 of the toothbrush handle part 2 has a rib-like and/or approximately half-shell shaped coupling piece 13 provided thereon that can be moved into locking engagement with the coupling insert 9 of the brush attachment. The frustum-shaped handle part neck 4 is split, so to speak, into a body part that is rigidly connected to the handle part housing and forms the actual handle part neck 4, and the movably supported coupling piece 13 that, in the non-locking starting position as it is shown, for example, in FIG. 4, essentially extends the contour of the handle part neck 4 and, together with this, forms the connecting frustum onto which the tubular connecting piece 7 of the brush attachment can be attached. The coupling piece is pushed into the position shown in FIG. 4 by a spring element 29 that is formed, for example, by a coil spring arranged in the handle part.

The coupling piece 13 of the handle part, which extends with its plane of symmetry in the longitudinal direction 12 of the handle part 2, is movably hinged to the handle part neck by means of a parallelogram link guide 17. As illustrated best by FIG. 3, the parallelogram link guide comprises two rotatable links 15 and 16 that are oriented parallel to one another and hinged with one end to the handle part neck 4 and with the other end to the coupling piece 13. The “two” links 15 and 16 can also be two link pairs that are arranged to the right and left of the drive shaft 5 in each case and hinged around common pivot axis pairs in each case, so that the coupling piece 13 is supported in a stable manner also against tilting transversely to the links.

As can be seen when comparing FIGS. 4 through 9, the coupling piece 13 can be pivoted back or moved back via the parallelogram link guide 17 from a frontal non-locking end position located at the front end of the handle part that forms the starting position, so to speak, against the force of the spring element 29 toward the handle part 2 into a locking second end position. The parallelogram link guide 17 forms an expanding mechanism 14 that expands the coupling piece 13 during transfer thereof from the frontal end position to the rearward end position transversely to the longitudinal direction of the toothbrush, so that the coupling piece 13 in the locking second end position, as it is shown by FIG. 9, radially stands out further than in the frontal first end position shown by FIG. 4. To this effect, the links 15 and 16 are arranged in such a way that they are inclined more flatly relative to the longitudinal axis of the toothbrush in the non-locking frontal end position and inclined more steeply in the locking rearward end position; cf. FIG. 4 as compared to FIG. 9. Advantageously, the links 15 and 16, when transferring the coupling piece 13 into the locking position thereof, move over the position perpendicular to the longitudinal direction of the toothbrush, so that an over-pressing of the parallelogram link guide 17 takes place before the locking end position is reached. In this way the coupling piece 13 and thus the brush attachment 3 is held in a stable manner in the locking, coupled position. To this effect the coupling insert 9 of the brush attachment 3 is advantageously adapted in the diameter thereof so as to match the expanding movement of the coupling piece 13, so that, during the over-pressing of the parallelogram link guide 17 a slight elastic deformation takes place and/or a snug precise fit with slight radial pressure onto the coupling piece 13 is achieved in the area around the locking position of the coupling 13. In this manner the brush attachment 3 is securely held on the toothbrush handle part 3.

As shown by FIGS. 4 through 9, the coupling insert 9 of the attachment has on its internal cylindrical surface an outwardly oriented depression 25 in the form of a window in the coupling insert 9, into which a radially projecting detent locking projection 18 can move on the coupling piece 13. Said detent locking projection 18 forms the engaging part 11 with which the coupling device 10 of the handle part locks the brush attachment 3 to the handle part neck 4.

Advantageously in the proximity to said depression 25 the coupling insert 9 has a radially inwardly projecting actuation projection 28 provided thereon that drives the coupling piece 3 and pushes it into the locking position thereof when the brush attachment 3 is being attached onto the handle part neck 4. The actuation projection 28 in the illustrated embodiment is arranged downstream, in the attachment direction, of the aforementioned depression 25, wherein when viewed radially, it projects further inward (toward the axis) than the section 30 of the coupling insert 9 situated upstream, in the insertion direction, of the depression 25; cf. FIG. 4. In the illustrated embodiment, the actuation projection 28 directly adjoins the depression 25, so that the abutting surface 20 transverse to the longitudinal direction of the attachment transitions at the actuation projection 28 extends flush into the edge surface of the depression; cf. FIG. 4.

This results in the following function: when the brush attachment 3 is being attached onto the handle part neck 4, the coupling piece 13 initially remains in the moved-in non-locking end position. The coupling insert 9 has in its slide-in region up to the depression 25 a clear width that, when viewed radially, is greater than the radial dimension of the detent locking projection 18 in the moved-in non-locking position of the coupling piece 13; cf. FIG. 4.

In this manner the brush attachment 3 can be pushed over the coupling piece 13 until the detent locking projection 18 thereof comes to rest in the region of the depression 25, as it is shown in FIG. 5. During the continued process of attaching the brush attachment 3, however, the coupling piece 13 hits its abutting surface 20 provided on the front end thereof, which also extends transversely to the longitudinal direction 12 of the handle part, against the abutting surface 26 on the actuation projection 28 of the coupling insert 9. This causes the coupling piece 13 to stand still, so to speak, wherein during the continued process of inserting the handle part neck, the coupling piece 13 is outwardly expanded by means of the parallelogram link guide 17 on the path of movement defined by same, as illustrated by FIGS. 6 to 8. The detent locking nose 18 accordingly moves into the depression 25. When the brush attachment 3 is being completely attached, the perpendicular position shown in FIG. 8 of the links 15 and 16 of the parallelogram link guide 17 is advantageously move over, such that the dead center position of the parallelogram link guide 17 is over-pressed. In the fully locked position, the links 15 and 16 are slightly inclined back toward the handle part 2; cf. FIG. 9.

When the brush attachment 3 is being removed, the coupling piece 13 is pivoted in the opposite direction back into its non-locking position. In this process, a driving surface 27 provided on the coupling insert 9 drives a driving surface 21 provided on the coupling piece 13 and thereby the coupling piece 13 in an axial direction. In the embodiment illustrated in the drawing, the driving surface 21 of the coupling piece 13 is formed by the rear of the detent locking projection 18 and extends essentially perpendicular to the longitudinal direction 12 of the handle part. On the coupling insert, 9 the driving surface 27 is formed by an edge surface of the depression 25.

Advantageously, the coupling piece 13 at the same time forms a control device 22 or a part thereof, that prevents the toothbrush drive from starting accidentally during the coupling and uncoupling of the brush attachment 3. The coupling piece 13 has, as a retarding means 23 on its inward side, a flattened region 24 that cooperates with a flattened region 31 of the drive shaft 5 on the circumferential surface. As shown by a comparison of FIGS. 4 and 9, the coupling piece 13 rests in its non-locking position with its flattened region 24 on the flattened region 31 of the drive shaft 5, so that the latter cannot rotate. When the coupling piece 13 moves out into its locking position, however, the drive shaft 8 is released; cf. FIG. 9.

Said retardation of the drive shaft 5 may be part of a travel safety and/or battery protection mechanism that switches off the drive motor when then drive shaft is retarded. By means of a suitable detection device, said control device 22 can detect whether the coupling piece 13 is retarding the drive shaft 5 or not. In particular, detection means 32 may be provided for this purpose that detect the level of the motor current. Namely, if the drive shaft 5 is retarded then the motor current rises above its normal level, so that when a specified motor current threshold is exceeded, it can be assumed that this results from a retardation of the drive shaft 5 and, accordingly, from a removed attachment. A cut-off device 33 of the control device 22 can turn off the drive motor in this case, so as to prevent the drive motor from being damaged or the disposable or rechargeable battery from discharging accidentally.

As shown in FIGS. 10 and 11, the expanding mechanism 14 can, in lieu of the previously described parallelogram link guide 17, also have a sliding guide in the form of a connecting link guide 34 for expanding the coupling piece 13. In the illustrated embodiment according to FIGS. 10 and 11, the coupling piece 13 comprises a guiding slide 35 in the form of two longitudinal-groove shaped, step-like angular guide grooves, into which two guide pins 36 engage, the diameter of which approximately corresponds to the width of the guide grooves, in order to achieve a substantially backlash-free sliding guidance of the coupling piece 13. In lieu of the two guide grooves illustrated in FIGS. 10 and 11, it is optionally possible that only one guide groove could be provided, optionally in combination with an additional support for the coupling piece 13, so that it would additionally experience a pivot movement during the expansion process. However, the connecting link guide with two guide pins 36 that is illustrated in FIGS. 10 and 11 is preferred.

Advantageously, said guiding slide 35 can comprise guide sections 37, 38, 39 having differently acute inclines toward the longitudinal direction 12 of the handle part, so that the lifting and expansion movement of the coupling piece 13 goes through multiple phases. Preferably, a more acutely inclined guide middle section 39 is provided that opens into less acutely inclined guide end sections 37 and 38; cf. FIG. 10. Said guide end sections 37 and 38 are advantageously oriented essentially parallel to the longitudinal direction 12 of the handle part, so that when said guide pins 36 are located in the region of these guide end sections 37 and 38, no lifting movement of the coupling piece 13 takes place and the latter is maintained at the respective expansion level free from axial forces. Said guide end sections 37 and 38 could optionally also be slightly inclined in opposite directions—compared to the incline of the guide middle section 39—so that when the end positions are being approached, a slight over-pressing takes place.

-   The incline of the guide middle section 39 is advantageously matched     to the features of the coupling device 10, for example especially to     the length of the attaching movement and the diameter of the handle     part neck, wherein an angle of incline in the range of approximately     45° to 80° was shown to be advantageous in the embodiment according     to FIG. 10.

Aside from the design of the expanding mechanism 14, the embodiment of FIGS. 10 and 11 essentially corresponds to the embodiment of the preceding figures, so that reference is made in this context to the preceding description and identical reference numerals are used for corresponding components.

The embodiment of FIGS. 10 and 11 essentially corresponds to the preceding figures in terms of function as well: when the brush attachment 3 is attached onto the handle part neck 4, the coupling piece 13 initially remains in its moved-in non-locking end position, as shown in FIG. 11. The coupling insert 9 has in its slide-in region up to the depression 25 a clear width that, when viewed radially, is greater than the radial dimension of the detent locking projection 18 of the coupling piece 13; cf. FIG. 11.

In this manner the brush attachment 3 can be pushed beyond the coupling piece 13 until the detent locking projection 18 thereof comes to rest in the region of the depression 25. During the continued process of attaching the brush attachment 3, however, the coupling piece 13 hits an abutting surface 20 provided on the front end thereof, which extends transversely to the longitudinal direction 12 of the handle part, against the abutting surface 26 on the actuation projection 28 of the coupling insert 9. This causes the coupling piece 13 to be axially driven during the continued process of attaching the brush attachment 13, thereby causing the coupling piece 13 to be moved in the connecting link guide 34. In this process, the coupling piece 13 is pushed radially outward via the inclined guide middle section 39, so that its detent locking projection 18 moves into the window-like depression 25 of the brush attachment 3; cf. FIG. 10.

As shown in FIGS. 10 and 11, the actuation projection 28 of the brush attachment 3 that drives the coupling piece 13 is designed in the form of a spring brace that locks on the handle part neck in the completely attached position, and forms a detent locking device in this respect. In particular, said actuation projection 28, when being moved into the interior of the handle part neck 4, can first radially elastically deflect at that location and slide over a handle part neck contour. Upon reaching the end position the actuation brace can snap into an undercut recess and spring back. In the illustrated embodiment, the actuation projection 28 is provided with a radially projecting detent locking nose that moves into a detent locking recess provided on the handle part neck 4; cf. FIG. 10. This achieves an added retaining of the brush attachment 3 in the attached position.

-   When the brush attachment 3 is being removed, the coupling piece 13     is pivoted in the opposite direction back into its non-locking     position. In his process, a driving surface 27 provided on the     coupling insert 9 drives the driving surface 21 provided on the     coupling piece 13 and thereby the coupling piece 13 in an axial     direction. At the same time the actuation projection 28 is unlocked     via an oblique surface on its detent locking projection 40; cf.     FIG. 10. During the continued process of pulling back, the coupling     piece 13 moves far enough radially inward in the connecting link     guide that the inner contour of the brush attachment 3 can be pulled     over the detent locking projection 18 of the coupling piece 13; cf.     FIG. 11. At the same time the coupling piece 13 sits with the     flattened region 24 located on the inside thereof on the flattened     region 31 of the drive shaft 5, which as a result is blocked.

Advantageously, dirt catching recesses 41 are provided on the fitting surfaces of the toothbrush handle part and attachment, into which dust particles, crumbs, or the like can disappear, so to speak, so that they do not interfere with the coupling process. For example, the dirt catching recesses 42 may be provided in the form of longitudinal-groove like corrugations 42 on the outer surface of the coupling piece and/or on the outer surface of the handle part neck 4; cf. FIGS. 10 and 11. 

1. A toothbrush handle part of an electric toothbrush (1) having a handle part neck (4) that can be inserted into the connecting piece (7) of an attachment, for example, a brush attachment (3), wherein a coupling device (10) having at least one engaging piece (11) for form-fitting and/or frictionally engaged interlocking thereof with the connecting piece (7) of the attachment is provided on the handle part neck (4), characterized in that the coupling device (10) has a coupling piece (13) that is movable in the longitudinal direction (12) of the handle part.
 2. The toothbrush handle part according to claim 1, wherein the coupling piece (13) is supported and/or designed in such a way that an axial movement of the coupling piece (13) produces a transverse movement of the engaging part (11) transversely to the longitudinal direction (12) of the handle part.
 3. The toothbrush handle part according to claim 1 or 2, wherein an expanding mechanism (14) is provided between the handle part neck (4) and the engaging part (11), though which the engaging part (11) can be outwardly expanded transversely to the longitudinal direction (12) of the handle part when the coupling piece (13) is being moved axially toward the handle part.
 4. The toothbrush handle part according to the preceding claim, wherein the expanding mechanism (14) is provided between the handle part neck (4) and the coupling piece (13), so that the coupling piece (13) can be outwardly expanded when being moved axially toward the handle part.
 5. The toothbrush handle part according to any of the two preceding claims, wherein the expanding mechanism (14) is designed in the form of a positive guide that prevents a transverse movement of the coupling piece (13) without an axial movement of the coupling piece (13) and/or vice versa.
 6. The toothbrush handle part according to any of the preceding claims 3 to 5, wherein the expanding mechanism (14) has at least one link (15) that is rotationally hinged at one end thereof to the handle neck part (4) and rotationally hinged at the other end thereof to the coupling piece (13).
 7. The toothbrush handle part according to any of the preceding claims, wherein the coupling piece (13) is hinged to the handle neck part (4) by means of a parallelogram link guide (17) comprising at least two links (15, 16) that are oriented approximately parallel to each other.
 8. The toothbrush handle part according to any of the preceding claims, wherein the coupling piece (13) is guided on a path of movement relative to the handle part neck (4) that, prior to reaching a locking position of the coupling piece (13) at an axial end of the path of movement provides for a radial over-pressing of the coupling piece (13) in which the coupling piece (13) is moved further out transversely to the longitudinal direction (12) of the handle part than in said locking position.
 9. The toothbrush handle part according to claim 7 and/or claim 8, wherein the links (15, 16) of the parallelogram link guide (17) are arranged in such a way that the links (15, 16) when being pivoted into the locking position of the coupling piece (13), move over a position that is oriented perpendicular to the longitudinal direction (12) of the handle part.
 10. The toothbrush handle part according to the preceding claim, wherein the links (15, 16) of the parallelogram link guide (17) in their end positions which correspond to the locking and unlocking position of the coupling piece (13), are differently acutely inclined toward the longitudinal direction (12) of the handle part.
 11. The toothbrush handle part according to any of the preceding claims, wherein the engaging part (11) is rigidly connected to the coupling piece (13), preferably integrally formed on the coupling piece (13) as one piece.
 12. The toothbrush handle part according to any of claims 1 to 6, wherein the expanding mechanism (14) comprises a sliding guide, preferably a connecting link guide (34), for the coupling piece (13) having a guide section (39) that is acutely angled toward the longitudinal direction (12) of the handle part.
 13. The toothbrush handle part according to the preceding claim, wherein the sliding guide has a plurality of guide sections (37, 38, 39) that are differently acutely angled toward the longitudinal direction (12) of the handle part, wherein preferably two link end sections (37, 38) are less acutely inclined than a guide middle section (39) situated therebetween.
 14. The toothbrush handle part according to any of the preceding claims, wherein the engaging part (11) has a detent contour that is matched in it shape to a counterpart of the attachment, preferably a radially projecting detent locking nose (18).
 15. The toothbrush handle part according to any of the preceding claims, wherein the coupling piece (13) has a capture section (19) that is matched in the shape and position thereof to a counterpart on the attachment, for capturing said counterpart on the attachment when the attachment is being attached onto the handle part neck (4) and for axially displacing the coupling piece (13).
 16. The toothbrush handle part according to the preceding claim, wherein the capture section (19) has an abutting surface (20) extending transversely to the longitudinal direction (12) of the handle part.
 17. The toothbrush handle part according to any of the preceding claims, wherein an engaging contour is provided on the engaging part (11), preferably in the form of a driving surface (21), for axially moving the coupling piece (13) back when the attachment is being removed from the handle part neck (4), said engaging contour is measured in such a way that said engaging contour, when the coupling piece (13) is moved transversely to the longitudinal direction (12) of the handle part, moves inward toward the handle part neck (4) out of engagement with the attachment.
 18. The toothbrush handle part according to any of the preceding claims, wherein the coupling device (10) has a control device (22) assigned to it for controlling a toothbrush drive depending upon the position of the coupling device (10).
 19. The toothbrush handle part according to the preceding claim, wherein the control device (22) has retarding means (23) for retarding, blocking, slowing down and/or switching off the toothbrush drive when the engaging part (11) of the coupling device (10) is in a position deviating from the locking position thereof.
 20. The toothbrush handle part according to the preceding claim, wherein the retarding means (23) have an engaging surface on the coupling piece (13) that can be moved into engagement in the moved-in non-locking position of the coupling piece (13) with a drive shaft of the handle part (2).
 21. The toothbrush handle part according to the preceding claim, wherein the retarding means (23) comprise a flattened region on the circumferential side on the coupling piece (13) that can be moved against a likewise flattened region provided on the circumferential side of the drive shaft of the handle part (2).
 22. The toothbrush handle part according to any of claims 18 through 21, wherein the control device (13) has a preferably electronic cut-off device (33) for switching off the drive motor when the drive shaft (5) is retarded.
 23. The toothbrush handle part according to the preceding claim, wherein the cut-off device (33) has detection means (32) for detecting the motor current and cut-off means for switching off the drive motor when a specified motor current is exceeded.
 24. The toothbrush handle part according to any of the preceding claims, wherein the coupling piece (14) forms a preferably rib-like shell part that forms, in the non-locking position of the coupling device (10), a part of the handle part neck contour, preferably approximately uniformly extending the handle part neck contour.
 25. The toothbrush handle part according to any of the preceding claims, wherein the handle part neck (4) has dirt catching recesses (41).
 26. The toothbrush handle part according to the preceding claim, wherein the dirt catching recesses (41) are designed in the form of a preferably longitudinal-groove like corrugations (42) of the fitting surface, which can be moved into engagement with the fitting surface of the attachment (3).
 27. The toothbrush handle part according to any of the preceding claims, characterized by a spring element (29) that pushes the coupling piece (13) in the longitudinal direction (12) of the handle part into an unlocking position, i.e. away from the grip portion of the handle part.
 28. An attachment, for example a brush attachment, for a toothbrush handle part, preferably according to any of the preceding claims, having an operating head (6) and a tubular connecting piece (7) connected to the operating head (6), said connecting piece (7) being placeable onto the handle part neck (4) of the toothbrush handle part, wherein the connecting piece (7) has a coupling part (9) for form-fitting and/or frictionally engaged locking of the connecting piece (7) on the handle part neck (4), characterized in that the coupling part (9) has on an internal cylindrical surface an outwardly oriented depression (25) and an abutting surface (26).
 29. The attachment according to the preceding claim, wherein the depression (25) forms a window-shaped locking detent depression.
 30. The attachment according to any of the two preceding claims, wherein an engaging part (11) of a coupling piece (13) of the handle part can be moved into the depression (25).
 31. The attachment according to any of the three preceding claims, wherein the abutting surface (26) is arranged adjoining the depression (25) in the longitudinal direction of the attachment.
 32. The attachment according to the preceding claim, wherein the abutting surface (26) transitions flush into an edge surface of the depression and/or at least partially forms an edge surface bounding the depression (25).
 33. The attachment according to the preceding claim, wherein the abutting surface (26) serves for the axial pushing back of the coupling piece of the handle part when the connecting piece (7) is being placed onto the handle part neck (4).
 34. The attachment according to any of claims 28 through 33, wherein a driving surface (27) is provided for axially driving the coupling piece (13) of the handle part when the connecting piece (7) is being removed from the handle part neck (4).
 35. The attachment according to the preceding claim, wherein the driving surface (27) is arranged adjoining the depression (25) in the longitudinal direction of the attachment, in particular forming a depression edge surface bounding the depression (25).
 36. The attachment according to the preceding claim, wherein the abutting surface (26) and the driving surface (27) are provided on opposite edges of the depression (25).
 37. The attachment according to any of claims 28 through 36, wherein the coupling part (9) has a coupling insert that is separate from the connecting piece (7), for example a coupling ring or a coupling sleeve.
 38. The attachment according to any of claims 28 through 36, wherein the coupling part (9) is formed in the connecting piece (7) as one piece.
 39. The attachment according to any of claims 28 through 38, wherein a detent locking hook is provided that can be moved into the handle part neck (4) of the toothbrush handle part (2) and can be moved into engagement with a detent contour on the toothbrush handle part neck (4).
 40. The attachment according to the preceding claim, wherein the detent locking hook has the abutting surface (26) for displacing the coupling part (13) of the toothbrush handle part and/or is designed in the form of a radially movable spring brace.
 41. The attachment according to any of claims 28 through 40, wherein the connecting piece (7) and/or the coupling part (9) thereof has dirt catching recesses.
 42. The attachment according to the preceding claim, wherein the dirt catching recesses are designed in the form of a preferably longitudinal-groove like corrugation of the fitting surface that can be moved into engagement with the fitting surface of the toothbrush handle part neck (4).
 43. A toothbrush having a toothbrush handle part according to any of claims 1 to 27 and an attachment according to any of claims 28 to
 42. 44. The toothbrush according to the preceding claim, wherein the depression (25) on the attachment is adjusted in terms of the shape and position thereof to the expandable engaging part (11) of the coupling device (10) of the handle part in such a way that during the process of placing the attachment on the handle neck part (4), the engaging part (11) of the coupling device (10) of the handle part can be moved precisely fitting into said depression (15).
 45. The toothbrush according to any of the two preceding claims, wherein the coupling part (9) of the attachment and the coupling piece (13) of the coupling device (10) of the handle part have capture sections provided thereon that mutually capture each other when the attachment is being attached onto the handle part neck (4), which are designed in such a way that when the attachment is being attached onto the handle part neck (4), they effect an axial actuating movement of the coupling piece (13) of the coupling device (10) of the handle part and slide off on one another transversely to the longitudinal direction of the toothbrush. 